Error Type

Dynamic Programming

• [N+1] for string
• A.charAt(N) ERROR
• Return not dp[N] or dp[N][M], but some MAX or MIN

LinkedList

• Remove Node p (setting p.next = null)
• break link (setting the left end's next = null)

Comparator

• private Comparator<ListNode> listNodeComparator = new Comparator<ListNode>() {
•         public int compare(ListNode left, ListNode right) {
•             if (left == null) {
•                 return 1;
•             } else if (right == null) {
•                 return -1
•             }
•             
•             return left.val - right.val;
•         }
•     };